Medical guide wire and process for production thereof

ABSTRACT

A medical guide wire ( 1 ) is made in which at least a fluororesin coating layer ( 13 ) is formed on the surface of a metal wire ( 11 ), wherein particulate matter is present in the fluororesin coating layer ( 13 ), and the fluororesin coating layer covers the particulate matter and at least some of the particulate matter is formed in surface protrusion-shaped projections ( 14 ). It is thus possible to provide a medical guide wire that is inexpensive to manufacture and whose strength is unaffected and frictional resistance is low, and manufacturing method for the same.

TECHNICAL FIELD

The present invention relates to medical guide wires used in guiding acatheter directly, or inserted through a blood vessel, into a person'sbody during a test or a medical procedure, and methods for manufacturingthe same.

BACKGROUND ART

Medical acts performed on the body impose a significant burden on thepatient, and thus testing and medical procedures on the body have cometo be performed by inserting a medical device such as a catheterdirectly into a body cavity in place of the conventional approach ofmaking an incision. When using a catheter in this manner, a guide wireis passed through a catheter that is to be introduced to a target sitewithin the body, and then the catheter is guided along the guide wire tothat target site.

When inserting a catheter, the guide wire serving as the guide isinserted first and then the catheter is inserted into the body along theguide wire, and when there is little clearance between the catheter andthe guide wire, or due to the blood influx at the time of insertion intothe body, frictional resistance occurs and causes the guide wire to comeinto intimate contact with the inner circumferential surface of thecatheter, increasing the likelihood of trouble. Consequently, to lowerthe frictional resistance between the guide wire and the catheter, theguide wire, that is, the core wire, is coated with fluororesin so thatthe guide wire can pass through the catheter with ease (JP H3-41966A).

However, although a guide wire whose core wire surface has been evenlycoated with a fluororesin exhibits lower frictional resistance due tothe low friction properties afforded by the fluororesin, the fluororesincomes into intimate contact with the inner circumferential surface ofthe catheter because it is applied evenly, and thus its effect was notsufficient. Accordingly, other proposals have been forwarded to furtherreduce the frictional resistance between the catheter and the guidewire, including providing the outer circumferential surface of the guidewire itself with an uneven shape having recessions and protrusions (JPH11-19217A), and wrapping a helical coil around its outside (JPH11-178930A, Tokuhyo 2000-509641).

However, in each of these conventional examples it was necessary toprocess the core material, and this complicated manufacturing, and therewere also problems such as a change in the properties of the wire, forexample its strength and modulus of elasticity, due to processing thecore material, and an increase in costs due to core material processing,and moreover, there was the problem that the frictional resistance wasnot significantly improved.

DISCLOSURE OF INVENTION

In order to solve the foregoing conventional problems, it is an objectof the present invention to provide a medical guide wire that isinexpensive to manufacture and whose strength is unaffected andfrictional resistance is low, and a manufacturing method for the same.

A medical guide wire of the present invention is a medical guide wire inwhich at least a fluororesin coating layer is formed on a surface of ametal wire, wherein particulate matter is present in the fluororesincoating layer, and the fluororesin coating layer covers the particulatematter and at least some of the particulate matter is formed in surfaceprotrusion-shaped projections.

A method for manufacturing a medical guide wire of the present inventionis a method for manufacturing a guide wire, in which at least afluororesin coating layer is formed on a surface of a metal wire, thatincludes mixing particulate matter for projections into a fluororesindispersion to prepare a coating solution, applying the solution to thesurface of the metal wire and drying the solution, and then baking byheating to at least the melting point of the fluororesin in thefluororesin dispersion, to cause particulate matter to be present in thefluororesin coating layer, wherein the fluororesin coating layer coversthe particulate matter and at least some of the particulate matter isformed in surface protrusion-shaped projections.

Another method for manufacturing a medical guide wire according to thepresent invention is a method for manufacturing a medical guide wire, inwhich a primer layer and a fluororesin coating layer are formed in thatorder on a surface of a metal wire, that includes mixing particulatematter into at least one solution selected from a primer solution and afluororesin dispersion solution, applying the primer solution and thefluororesin solution to the surface of the metal wire in that order anddrying them, and then, in a final process, baking by heating to at leastthe melting point of the fluororesin in the fluororesin dispersion suchthat the fluororesin coating layer of the outermost layer covers theparticulate matter and at least some of the particulate matter is formedin surface protrusion-shaped projections.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a SEM photograph (220×) external view of the fluororesincoated wire obtained in Working Example 1 of the present invention.

FIG. 2 is a schematic cross-sectional view of the same.

FIG. 3 is an explanatory diagram showing the method for measuring thefrictional resistance in the working examples of the present invention.

FIG. 4 is a SEM photograph (220×) external view of the fluororesincoated wire obtained in Comparative Example 1 of the present invention.

FIG. 5 is a SEM photograph (220×) external view of the fluororesincoated wire obtained in Comparative Example 2 of the present invention.

FIG. 6 is a SEM photograph (220×) external view of the fluororesincoated wire obtained in Working Example 3 of the present invention.

FIG. 7 is a schematic cross-sectional view of the same.

FIG. 8 is an explanatory diagram showing the method for measuring theheight of the projections in the working examples of the presentinvention.

-   1,20 fluororesin coated wire-   2 tube made of resin-   3 metal jig-   4 clip-   5 tensile tester-   7 fastened chuck-   11,21 superelastic alloy wire-   12,22 primer layer-   13,23 fluororesin coating layer-   14,24 projections-   25 aluminum borate particles

BEST MODE FOR CARRYING OUT THE INVENTION

In the present invention it is possible to provide the particulatematter in either or both the primer layer and the fluororesin coatinglayer. In a final process, by baking by heating to at least the meltingpoint of the fluororesin in the fluororesin dispersion, the fluororesincoating layer of the outermost layer covers the particulate matter.Particulate matter having a predetermined average particle diameter isused, and of these, comparatively large particles and agglomeratedparticles are formed in surface protrusion-shaped projections.

In a preferable example of the present invention, the fluororesincoating layer and the protruding projection-like fluororesin portionsare baked as a single unit. Thus, the projection-like fluororesinparticles are formed in smooth projections, and this contributes tolowering the frictional resistance. In other words, if the projectionsare smooth, then an object (resin tube) that comes into contact withthem makes point contact, lowering the frictional resistance. As aresult, this is useful for the medical guide wire for catheters, forexample.

In the foregoing, whether or not the projections are smooth isdetermined based on observations made at 200× magnification by scanningelection microscope (SEM). When the magnification ratio is too small(for example, observations by the unaided eye), many of the projectionswill appear relatively smooth, whereas when the magnification ratio istoo high (for example, 1000×), then many of the projections will appearextremely steep. Consequently, choosing the magnification ratio is veryimportant. It should be noted that at a magnification ratio of 200×, thediameter portion of a medical guide wire whose diameter is approximately0.35 mm fits into a single field of view, allowing the entire diameterportion to be observed and thus is favorable.

If the fluororesin coating layer includes particulate matter, then it ispreferable that the particulate matter is fluororesin. The two beingcompatible allows them to be baked into a more robust single unit.

It is preferable that the fluororesin coating layer and the fluororesinprojections include at least one selected from polytetrafluoroethylene(PTFE), tetrafluoroethylene-perfluoroalkylvinyl ether copolymer (PFA),polychlorotrifluoroethylene (PCTFE), polyvinylidene fluoride (PVDF),polyvinyl fluoride (PVF), tetrafluoroethylene-hexafluoropropylenecopolymer (FEP), and tetrafluoroethylene-ethylene copolymer (PETFE). Ofthese, at least one selected from polytetrafluoroethylene (PTFE) andtetrafluoroethylene-perfluoroalkylvinyl ether copolymer (PFA) ispreferable. This is because of their relatively high melting point andthe fact that they are safe for the human body.

It is preferable that the thickness of the fluororesin coating layer isat least 1 μm and not more than 50 μm. This is because this thicknessdoes not effect the medical operation of the wire. It is also preferablethat the average height of the projections is at least 0.1 μm and notmore than 20 μm. This range is ideal for lowering friction. It is alsopreferable that the fluororesin coating layer surface has a mixture offlat portions and numerous projections. This shape is ideal forimproving the friction characteristics. It is further preferable thatthe density of the protrusion-shaped fluororesin portions is at least anaverage of 1 per 0.01 mm² in order to lower friction.

Also, whereas it is preferable to have projection-like protrusion shapesin the fluororesin coating layer surface, to improve the roundedness ofthese projections, it is preferable that a fluororesin is coated onto awire surface and baked to achieve a fluororesin coating layer by meltingto form flat portions and also baking to melt the fluororesin particlesfor projections in a single unit with the fluororesin coating layer andform projection portions that after baking take on a smooth particleshape, thereby contributing to their roundness. To this end, it ispreferable that non-baked fluororesin particles are dispersed in liquidto form the fluororesin dispersion, and also that particles that havebeen baked are mixed in with the fluororesin particles for projections.

It is also preferable to mix fluororesin having different meltingpoints, and by mixing fluororesin particles having a higher meltingpoint than the fluororesin dispersion into the fluororesin dispersion,which has a lower melting point, it is possible to form a fluororesincoating layer with excellent roundedness in which deformation of thefluororesin particles due to melting is suppressed. For example, it ispossible to mix PTFE (melting point 327° C.) particles for projectionsinto a dispersion of FEP (melting point 255 to 265° C.) or PFA (meltingpoint 305° C.), or to mix PTFE particles for projections that have beenbaked into a non-baked PTFE dispersion, and depending on the conditions,various combinations of these are possible.

A method for manufacturing a medical guide wire of the present inventionis a method for manufacturing a guide wire, in which a fluororesin layeris formed on a surface of a metal wire, that includes mixing fluororesinparticles for projections into a fluororesin dispersion to prepare acoating solution, applying the solution to the surface of the metalwire, and then baking by heating to at least the melting point of thefluororesin dispersion, thereby forming a fluororesin coating andprojection-like fluororesin portions protruding from the fluororesincoating as a single unit on the surface of the metal wire, formingrounded projections.

The method for applying the fluororesin dispersion or the primersolution to the guide wire surface can be any one of brushing, spraying,or the like, but in order to achieve a uniform application, a dippingmethod is preferable. The temperature at which the fluororesin is bakedis between 300 and 450° C., and thus after baking the fluororesin coatedwire, the fluororesin is cooled quickly from a molten state, therebyannealing the metal wire and preventing the loss of rigidity as well asobtaining a hard coating layer due to the fluororesin layer coolingquickly. Here, cooling quickly means cooling of the fluororesin from amolten state at a rate of about 50 to 100° C. per second. The preferableconditions can be determined based on the wire diameter and material ofthe metal wire and the thickness and baking temperature of thefluororesin.

In the method of the invention, it is preferable that the fluororesinsolid content concentration in the fluororesin dispersion for coating is20 to 60 wt %. Within this range, the dispersion is stable.

It is preferable that when A is an amount of the fluororesin particlesfor forming projections that is added and B is the solid content of thefluororesin dispersion, then [A/(A+B)]×100 is 1 to 60 wt %. This isbecause it gives favorable low friction properties. It is preferablethat the average particle diameter of the fluororesin microparticles forcoating within the fluororesin dispersion is approximately 0.20 to 0.30μm when measured by a light dispersion method. It is also preferablethat the average particle diameter of the fluororesin particles forprojections is at least 0.5 and not more than 30 μm. This range is idealfor lowering friction. It should be noted that if the diameter of thefluororesin particles for projections is larger than the thickness ofthe fluororesin coating, then because they are baked into a single unitwith the fluororesin for coating, most are deformed due to melting andbecome smooth projections. If the diameter of the fluororesin particlesfor projections is smaller than the thickness of the fluororesincoating, then the amount of fluororesin particles for projections thatis added can be increased to stack the particles on one another andthereby cause them to protrude from the coating.

In the present invention it is possible to mix particulate matter intothe primer layer. By doing this, the fluororesin coating layer, which isthe outermost layer, covers the particulate matter, allowing theparticulate matter to form protrusion-shaped surface projections. Here,the primer layer is a layer for increasing the intimacy of contactbetween the metal surface of the guide wire and the outermostfluororesin layer. In this case, it is preferable that the particulatematter is fluororesin or a heat-resistant substance having a highermelting point than the fluororesin coating layer. This is becauseprojections of particle are formed conspicuously after the fluororesinis baked. The particulate matter can be at least one type of particleselected from fluororesin, glass, metal, plastic, inorganic powder, andceramic. It is preferable that the average particle diameter of theparticulate matter is at least the film thickness of the primer layer,and preferably the average particle diameter is in the range of 0.5 to30 μm. It is also preferable that the thickness of the fluororesincoating layer is at least 1 μm and not more than 50 μm. It is alsopreferable that the average height of the projections is at least 0.1 μmand not more than 20 μm. It is also preferable that the amount ofparticulate matter that is present is 1 to 50 wt % with respect to thesolid content mass of the primer solution.

A metal wire that has a uniform thickness or whose tip is tapered can beemployed favorably as the metal wire in the present invention. The wirematerial is preferably a superelastic alloy, and for example is Ti—Ni(Ni: 49-51 atomic %, including Ti—Ni to which a third element has beenadded), Cu—Al—Zn (Al: 3-8 atomic %, Zn: 15-28 atomic %), Fe—Mn—Si (Mn:30 atomic %, Si: 5 atomic %), Cu—Al—Ni (Ni: 3-5 atomic %, Al: 28-29atomic %), Ni—Al (Al: 36-38 atomic %), Mn—Cu (Cu: 5-35 atomic %), orAu—Cd (Cd: 46-50 atomic %). These alloys are known as superelasticalloys or shape memory alloys. Of these, a Ti—Ni alloy is preferable.Its thickness preferably is selected based on the inner diameter of thecatheter with which it is to be used in combination. More specifically,wires having a diameter of approximately 0.3 mm to 1 mm are frequentlyused.

WORKING EXAMPLES

Hereinafter, the present invention is described in more specific detailusing working examples.

(1) Method of Measuring the Frictional Resistance

As shown in FIG. 3, a polyurethane resin tube (inner diameter 2.5 mm,outer diameter 4.0 mm, length 200 mm) 2 is fixedly adhered over half itscircumference to a metal jig 3 having a diameter of 90 mm, and the jig 3is attached to a fastened chuck 7 of a tensile tester.

Next, a fluororesin coated wire 1 is inserted into the polyurethaneresin tube and one end of the wire is fastened to a clip 4 of thetensile tester 5, while the other free end is pulled at a velocity of 50mm per minute in the direction of an arrow 6, and by measuring the loadat this time, the frictional resistance between the wire 1 and thepolyurethane resin tube was measured. The smaller the tensile strength,the smaller the frictional resistance. The measurement was performed bymeasuring the frictional resistance over any 50 mm portion of the guidewire, and recording those values to a chart and calculating an averagevalue from the data.

(2) Method of Measuring the Height of the Projections Coated byFluororesin

Measurement was performed under the following conditions using the superdepth-shape measuring microscope “VK-8550” made by KEYENCE CORPORATIONof Japan.

-   Emission Laser: semiconductor laser, wavelength 685 nm-   Output: 0.45 mW-   Magnification Ratio: 100×-   Measurement Depth: 5 μm-   Movement Pitch: 0.05 μm-   Laser Scan: 9 Hz-   Laser Emission Angle: Vertical (emission straight downward from    above, and reflection light is received by a light-receiving    portion)

Regarding the measuring method, as shown in FIG. 8 a laser light a1 isemitted straight down and the reflection light a2 is received by alight-receiving portion that is not shown, and from its focal length thedistance (depth) of the section in question is measured. Projections 14also are measured in this fashion, emitting a laser light b1 andreceiving reflection light b2, and from that focal length obtaining thedistance of that position by measurement. In other words, the unevennessof a sample is successively obtained by measurement over a fixed area ofthe sample from that focal length, calculating the height of theprojections 14 regarding the a1 emission portions as flat portions.Measurements are calculated as the average value of five measured valuesper sample.

Working Example 1

A primer solution (“855-300” made by Dupont) having a 35% solid portionconcentration) adjusted to a viscosity of 110 cp (23° C.) was coatedonto a 2 m length, 0.35 mm diameter Ti—Ni (Ni: 49-51 atomic %)superelastic alloy wire to a dried thickness of approximately 1 μm andthen dried naturally at room temperature for 10 minutes. It was thenheated at 150° C. for 30 minutes.

Separately, a fluororesin dispersion for coating (“855-510” made byDupont) was used as the fluororesin of the outermost layer. Thefluororesin solid concentration was 50 wt %. PTFE particles for formingprojections (“L150J” made by Asahi Glass) (average particle diameterapproximately 9 μm) were added to this dispersion to 20 wt % withrespect to the fluororesin mass of the dispersion and then mixed, andthis was taken as the coating liquid.

The coating liquid was coated over the wire, which had been coated bythe primer solution, dried naturally at room temperature (25° C.) for 1minute, heated at 200° C. for 10 minutes, then baked at 450° C. for 1minute and cooled to room temperature. The thickness of flat portions ofthe fluororesin coating layer was approximately 5 μm, and the averageheight of projections was approximately 3.5 μm.

FIG. 1 shows the external appearance of the fluororesin coated wireobtained in this manner. FIG. 1 is a scanning electron microscope (SEM)photograph taken at 200× magnification. It is clear from FIG. 1 that afluororesin coating layer and projections at a ratio of at least anaverage of 1 per 0.01 mm² are formed in the fluororesin coating layersurface, that the fluororesin particles and the fluororesin are bakedinto a single unit, and that the projection-like fluororesin particlesare formed in smooth protrusions.

FIG. 2 is a schematic cross-sectional view of FIG. 1. The fluororesincoated wire 1 is made of a primer layer 12, a fluororesin coating layer13, and projections 14 due to the fluororesin particles, baked into asingle unit on the surface of a superelastic alloy wire 11.

The frictional resistance of the fluororesin coated wire thus obtainedwas measured. The result was an average frictional resistance value forthe wire of Working Example 1 of 2.0 g.

Working Example 2

Other than using a dispersion in which microparticles of PFA, which havea lower melting point than PTFE, have been dispersed for the fluororesincoating dispersion for the coating of Working Example 1 and changing thebaking temperature when baking to form the fluororesin coating, the sameexperiment as that of Working Example 1 was performed. PTFE particlesfor forming projections (average particle diameter approximately 9 μm)were added to the dispersion of PFA microparticles to 20 wt % withrespect to the fluororesin mass and mixed and then coated onto a 2 mlength, 0.35 mm diameter superelastic alloy wire. After coating wasfinished, the result was dried naturally at room temperature for 1minute, heated at 200° C. for 10 minutes, then baked at 380° C. for 1minute and cooled to room temperature. The thickness of the flatportions of the fluororesin coating was approximately 5 μm, and theaverage height of the projections was approximately 4 μm. The averagefrictional resistance value of the wire of Working Example 2 was 1.8 g.

Comparative Example 1

Other than no PTFE particles for forming projections being added to thefluororesin dispersion in Working Example 1, the same fluororesincoating as in Working Example 1 was formed.

FIG. 4 shows the external appearance of the fluororesin coated wire.FIG. 4 is a scanning electron microscope (SEM) photograph taken at 200×magnification. It is clear from FIG. 4 that a fluororesin coating layerhaving a uniform thickness was formed.

The frictional resistance value of this fluororesin coated wire wasmeasured in the same manner as in Working Example 1, and the averagefrictional resistance value of the wire was found to be 4.5 g.

Comparative Example 2

PTFE particles having an average particle diameter of 9 μm were appliedas a fine powder over the wire surface and the fluororesin was baked for1 minute at a temperature of 450° C.

FIG. 5 shows the external appearance of the fluororesin coated wire.FIG. 5 is a scanning electron microscope (SEM) photograph taken at 200×magnification. It is clear from FIG. 5 that the fluororesin coatinglayer has an uneven shape.

The frictional resistance of this fluororesin coated wire was measuredas in Working Example 1, and the average frictional resistance value ofthe wire was found to be 3.8 g.

Working Example 3

A 2 m length, 0.35 mm diameter Ti—Ni (Ni: 49-51 atomic %) superelasticalloy wire was prepared. Next, 10 wt % aluminum borate “PF03” (made byShikoku Chemicals Corporation) having a 3 μm average particle diameterwas mixed in and dispersed to “855-300” (made by Dupont) having a 35%solid concentration to serve as a primer solution, and its viscosity wasadjusted to 110 cp (23° C.). The primer was then coated by an immersionmethod until a dried thickness of approximately 1.0 μm, dried naturallyat room temperature for 10 minutes, and then heated at 150° C. for 30minutes. Regarding the dried primer coating surface, the numerousaluminum borate projections precipitated on the wire surface wereapplied along with the primer coating.

Next, a fluororesin dispersion for coating (“AD-1” made by Asahi Glass),where the average diameter of the fluororesin microparticles made ofPTFE was measured by light dispersion to be approximately 0.20 μm, wasused for the outermost fluororesin layer. The fluororesin solid contentconcentration was 60 wt %, and using (Triton) polyoxyethylene (10)octylphenyl ethyl was adjusted to a viscosity of 150 CP, and thisdispersion was taken as the coating liquid of the outermost fluororesinlayer.

This coating liquid was coated by dripping onto the surface of the wirethat had been coated with the primer solution, dried naturally at roomtemperature for 1 minute, heated at 200° C. for 10 minutes, then bakedat 400° C. for 1 minute and cooled to room temperature. The thickness ofthe flat portions of the fluororesin coating layer was approximately 6μm, and the average height of the projections was approximately 2.0 μm.

FIG. 6 shows the external appearance of the fluororesin coated wireobtained in this manner. FIG. 6 is a scanning electron microscope (SEM)photograph taken at 200× magnification. It is clear from FIG. 6 that aguide wire having a coating layer in which the projection-like shapes ofthe aluminum borate particles mixed into the primer solution were formedas rounded projections coated by the fluororesin on the fluororesincoating layer surface was obtained.

FIG. 7 is a schematic cross-sectional view of the guide wire of thisworking example. A fluororesin coated wire 20 is made of a primer layer22, to which aluminum borate particles 25 have been mixed, and afluororesin coating layer 23 layered onto the surface of a superelasticalloy wire 21, and the projections 24 in which the aluminum borateparticles 25 are coated by the fluororesin layer are coated such thatthey form smooth projection shapes.

The average frictional resistance value of the fluororesin coated wirethus obtained was 1.5 g.

Working Example 4

To the primer solution of Working Example 3, PTFE particles (“L150J”made by Asahi Glass) (9 μm average particle diameter) were added inplace of the aluminum borate to 20 wt % with respect to the solidconcentration of the primer solution and this was mixed, and then thisprimer solution was coated by immersion to a thickness of 2 μm onto a 2m length, 0.35 mm diameter superelastic alloy wire. The primer solutionwas then dried naturally at room temperature for 10 minutes and heatedat 150° C. for 30 minutes and dried. Regarding the dried primer coatedsurface, the numerous fluororesin projections precipitated on the wiresurface were applied along with the primer coating. Then, coating byimmersion using a dispersion in which microparticles of PFA, which havea lower melting point than PTFE, are dispersed was performed, this wasdried naturally at room temperature for 1 minute, heated at 200° C. for10 minutes, then baked at 380° C. for 1 minute and cooled to roomtemperature. The thickness of the flat portions of the fluororesincoating was approximately 7 μm, and the height of the projections wasapproximately 5 μm. The average frictional resistance value was 1.8 g.

It is clear from the above working examples and comparative examplesthat the wire of the present invention, in which a fluororesin coatinglayer and fluororesin particles for forming projections are baked as asingle unit and the projection-like fluororesin particles form smoothprotrusions, had the lowest frictional resistance value.

INDUSTRIAL APPLICABILITY

With the medical guide wire of the present invention, the fluororesincoating layer and the projections made of particulate matter protrudingfrom the fluororesin coating layer surface are baked into a single unitand the protrusions are formed rounded, and thus the frictionalresistance between the catheter and the guide wire can be reduced,making the action of inserting the catheter into the body easy. Also, itis not necessary to process, for example deform, the core materialitself, and thus characteristics of the core material such as itsstrength and modulus of elasticity can be utilized as they are.

With the method of the present invention it is possible to effectively,efficiently, and inexpensively manufacture the medical guide wire of thepresent invention.

1. A medical guide wire in which at least a fluororesin coating layer isformed on a surface of a metal wire, wherein the metal wire has auniform thickness or a tapered tip; wherein particulate matter ispresent in the fluororesin coating layer, and the fluororesin coatingand the particulate matter are baked as a single unit; and wherein thefluororesin coating layer covers the particulate matter and at leastsome of the particulate matter is formed in surface protrusion-shapedprojections.
 2. The medical guide wire according to claim 1, wherein aprimer layer is further formed within the fluororesin coating layer;wherein particulate matter is present in at least one layer selectedfrom the primer layer and the fluororesin coating layer; and wherein thefluororesin coating layer of the outermost layer covers the particulatematter and at least some of the particulate matter is formed in surfaceprotrusion-shaped projections.
 3. The medical guide wire according toclaim 1, wherein the fluororesin coating layer includes particulatematter, the particulate matter is fluororesin, and the fluororesincoating and the particulate matter are baked as a single unit.
 4. Themedical guide wire according to claim 1, wherein the fluororesin coatinglayer and the particulate matter include at least one selected from thegroup consisting of polytetrafluoroethylene (PTFE),tetrafluoroethylene-perfluoroalkylvinyl ether copolymer (PFA),polychlorotrifluoroethylene (PCTFE), polyvinylidene fluoride (PVDF),polyvinyl fluoride (PVF), tetrafluoroethylene-hexafluoropropylenecopolymer (FEP), and tetrafluoroethylene-ethylene copolymer (PETFE). 5.The medical guide wire according to claim 1, wherein the thickness ofthe fluororesin coating layer is at least 1 μm and not more than 50 μm.6. The medical guide wire according to claim 1, wherein the averageheight of the projections is at least 0.1 μm and not more than 20 μm. 7.The medical guide wire according to claim 1, wherein the fluororesincoating layer surface has a mixture of flat portions and numerousprotrusion-shaped projections.
 8. The medical guide wire according toclaim 1, wherein the density of the protrusion-shaped projections is atleast an average of 1 per 0.01 m².
 9. The medical guide wire accordingto claim 2, wherein the particulate matter is present in the primerlayer, and the particulate matter is fluororesin or a heat-resistantsubstance having a higher melting point than the fluororesin coatinglayer.
 10. The medical guide wire according to claim 9, wherein theparticulate matter is at least one selected from the group consisting ofglass particles, metal particles, plastic particles, inorganicparticles, and ceramic particles.
 11. The medical guide wire accordingto claim 9, wherein an average particle diameter of the particulatematter is at least the film thickness of the primer layer, and theaverage particle diameter is in a range of 0.5 to 30 μm.
 12. A methodfor manufacturing a medical guide wire in which at least a fluororesincoating layer is formed on a surface of a metal wire, wherein the metalwire has a uniform thickness or a tapered tip; wherein the methodcomprises: mixing particulate matter for projections into a fluororesindispersion to prepare a coating solution; and applying the solution tothe surface of the metal wire and drying the solution, and then bakingby heating to at least the melting point of the fluororesin in thefluororesin dispersion; thereby causing particulate matter to be presentin the fluororesin coating layer; wherein the fluororesin coating layercovers the particulate matter, the fluororesin coating layer and theparticulate matter are baked as a single unit, and at least some of theparticulate matter is formed in surface protrusion-shaped projections.13. A method for manufacturing a medical guide wire in which a primerlayer and a fluororesin coating layer are formed in that order on asurface of a metal wire, wherein the metal wire has a uniform thicknessor a tapered tip; wherein the method comprises: mixing particulatematter into at least one solution selected from a primer solution and afluororesin dispersion solution; applying the primer solution and thefluororesin dispersion solution to the surface of the metal wire in thatorder and drying them; and then, in a final step, baking by heating toat least the melting point of the fluororesin in the fluororesindispersion such that the fluororesin coating layer of the outermostlayer covers the particulate matter and at least some of the particulatematter is formed in surface protrusion-shaped projections.
 14. Themethod for manufacturing a medical guide wire according to claim 12,wherein a fluororesin solid content concentration in the fluororesindispersion solution for coating is 20 to 60 wt %.
 15. The method formanufacturing a medical guide wire according to claim 12, wherein when Ais an amount of the particulate matter that is added and B is the solidcontent of the fluororesin dispersion, then [A/(A+B)]×100 is 1 to 60 wt%.
 16. The method for manufacturing a medical guide wire according toclaim 12, wherein an average particle diameter of the particulate matteris 0.5 to 30 μm.
 17. The method for manufacturing a medical guide wireaccording to claim 13, wherein particulate matter is mixed into theprimer resin solution to prepare a coating solution.
 18. The method formanufacturing a medical guide wire according to claim 17, wherein theamount of particulate matter that is present is 1 to 50 wt % withrespect to the solid content mass of the primer resin solution.